Methods for identifying resources of a new radio physical downlink control channel which have been preempted by ultra-reliable low latency communication

ABSTRACT

Methods and systems for detecting an enhanced massive mobile broadband (eMBB) physical downlink control channel (PDCCH) in the presence of for ultra-reliable low latency communication (URLLC) users are disclosed. A eMBB wireless transmit/receive unit (WTRU) may receive a eMBB control resource set (CORESET) configuration for a CORESET including a PDCCH preemption indicator. If PDCCH preemption is enabled based on the PDCCH preemption indicator, the eMBB WTRU may identify and remove preempted resource element groups (REGs) in the eMBB CORESET by comparing channel estimates for each REG bundle in the eMBB CORESET. The WTRU may perform channel estimation based on remaining REGs in the eMBB CORESET and detect the PDCCH by performing blind decoding, based on a received signal, on the remaining REGs in the eMBB CORESET.

This application is the U.S. National Stage, under 35 U.S.C. § 371, ofInternational Application No. PCT/US2019/012855 filed Jan. 9, 2019,which claims the benefit of U.S. Provisional Application Ser. No.62/615,825, filed Jan. 10, 2018, and U.S. Provisional Application Ser.No. 62/715,940, filed Aug. 8, 2018, the contents of which are herebyincorporated by reference herein.

BACKGROUND

In New Radio (NR) for Fifth Generation (5G) wireless systems, thestructure and design for the physical downlink control channel (PDCCH)uses two transmission modes of interleaving units and non-interleavingunits known as Resource Element Group (REG) bundles. Each REG bundleconsists of multiple REGs in time or frequency for joint channelestimation. Slot-based and non-slot-based transmissions and differentrates of monitoring for PDCCH are also defined in NR for 5G wirelesssystems.

SUMMARY

Methods and systems for detecting an enhanced massive mobile broadband(eMBB) physical downlink control channel (PDCCH) in the presence of forultra-reliable low latency communication (URLLC) users are disclosed. AeMBB wireless transmit/receive unit (WTRU) may receive a eMBB controlresource set (CORESET) configuration for a CORESET including a PDCCHpreemption indicator. If PDCCH preemption is enabled based on the PDCCHpreemption indicator, the eMBB WTRU may identify and remove preemptedresource element groups (REGs) in the eMBB CORESET by comparing channelestimates for each REG bundle in the eMBB CORESET. The WTRU may performchannel estimation based on remaining REGs in the eMBB CORESET anddetect the PDCCH by performing blind decoding, based on a receivedsignal, on the remaining REGs in the eMBB CORESET. If PDCCH preemptionis not enabled, the WTRU may perform channel estimation on each REGbundle in the eMBB CORESET and detect the PDCCH by performing blinddecoding, based on the received signal, on all REGs in the eMBB CORESET.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawings,wherein like reference numerals in the figures indicate like elements,and wherein:

FIG. 1A is a system diagram illustrating an example communicationssystem in which one or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram illustrating an example wirelesstransmit/receive unit (WTRU) that may be used within the communicationssystem illustrated in FIG. 1A according to an embodiment;

FIG. 1C is a system diagram illustrating an example radio access network(RAN) and an example core network (CN) that may be used within thecommunications system illustrated in FIG. 1A according to an embodiment;

FIG. 1D is a system diagram illustrating a further example RAN and afurther example CN that may be used within the communications systemillustrated in FIG. 1A according to an embodiment;

FIG. 2 is a scheduling diagram of an example scheduling method forpartially preempting the physical downlink control channel (PDCCH) forenhanced massive mobile broadband (eMBB) WTRUs in the presence of PDCCHfor ultra-reliable low latency communication (URLLC) WTRUs;

FIG. 3 is a flow diagram of an example method for partial preemption ofPDCCH for eMBB in the presence of PDCCH for URLLC;

FIG. 4 is another scheduling diagram of an example scheduling method forpartially preempting the PDCCH for eMBB WTRUs in the presence of PDCCHfor URLLC WTRUs;

FIG. 5 is a scheduling diagram of an example scheduling method for fullypreempting the PDCCH for eMBB WTRUs when overlapped with the PDCCH forURLLC WTRUs;

FIG. 6 is a scheduling diagram of an example method for transmission ofthe same downlink control information (DCI) over two PDCCH candidates oftwo different sets of search spaces on a same control resource set(CORESET); and

FIG. 7 shows a flow diagram of an example WTRU procedure for PDCCHrepetition through multi-CORESET search spaces together with softcombination for blind detection.

DETAILED DESCRIPTION

FIG. 1A is a diagram illustrating an example communications system 100in which one or more disclosed embodiments may be implemented. Thecommunications system 100 may be a multiple access system that providescontent, such as voice, data, video, messaging, broadcast, etc., tomultiple wireless users. The communications system 100 may enablemultiple wireless users to access such content through the sharing ofsystem resources, including wireless bandwidth. For example, thecommunications systems 100 may employ one or more channel accessmethods, such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailunique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM(UW-OFDM), resource block-filtered OFDM, filter bank multicarrier(FBMC), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a RAN104/113, a CN 106/115, a public switched telephone network (PSTN) 108,the Internet 110, and other networks 112, though it will be appreciatedthat the disclosed embodiments contemplate any number of WTRUs, basestations, networks, and/or network elements. Each of the WTRUs 102 a,102 b, 102 c, 102 d may be any type of device configured to operateand/or communicate in a wireless environment. By way of example, theWTRUs 102 a, 102 b, 102 c, 102 d, any of which may be referred to as a“station” and/or a “STA”, may be configured to transmit and/or receivewireless signals and may include a user equipment (UE), a mobilestation, a fixed or mobile subscriber unit, a subscription-based unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watchor other wearable, a head-mounted display (HMD), a vehicle, a drone, amedical device and applications (e.g., remote surgery), an industrialdevice and applications (e.g., a robot and/or other wireless devicesoperating in an industrial and/or an automated processing chaincontexts), a consumer electronics device, a device operating oncommercial and/or industrial wireless networks, and the like. Any of theWTRUs 102 a, 102 b, 102 c and 102 d may be interchangeably referred toas a UE.

The communications systems 100 may also include a base station 114 aand/or a base station 114 b. Each of the base stations 114 a, 114 b maybe any type of device configured to wirelessly interface with at leastone of the WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to oneor more communication networks, such as the CN 106/115, the Internet110, and/or the other networks 112. By way of example, the base stations114 a, 114 b may be a base transceiver station (BTS), a Node-B, an eNodeB, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller,an access point (AP), a wireless router, and the like. While the basestations 114 a, 114 b are each depicted as a single element, it will beappreciated that the base stations 114 a, 114 b may include any numberof interconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 104/113, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals on one or morecarrier frequencies, which may be referred to as a cell (not shown).These frequencies may be in licensed spectrum, unlicensed spectrum, or acombination of licensed and unlicensed spectrum. A cell may providecoverage for a wireless service to a specific geographical area that maybe relatively fixed or that may change over time. The cell may furtherbe divided into cell sectors. For example, the cell associated with thebase station 114 a may be divided into three sectors. Thus, in oneembodiment, the base station 114 a may include three transceivers, i.e.,one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and mayutilize multiple transceivers for each sector of the cell. For example,beamforming may be used to transmit and/or receive signals in desiredspatial directions.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet(UV), visible light, etc.). The air interface 116 may be establishedusing any suitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104/113 and the WTRUs 102 a,102 b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 115/116/117 using wideband CDMA (WCDMA).WCDMA may include communication protocols such as High-Speed PacketAccess (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-SpeedDownlink (DL) Packet Access (HSDPA) and/or High-Speed UL Packet Access(HSUPA).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as Evolved UMTS TerrestrialRadio Access (E-UTRA), which may establish the air interface 116 usingLong Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/orLTE-Advanced Pro (LTE-A Pro).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as NR Radio Access, which mayestablish the air interface 116 using New Radio (NR).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement multiple radio access technologies. For example, thebase station 114 a and the WTRUs 102 a, 102 b, 102 c may implement LTEradio access and NR radio access together, for instance using dualconnectivity (DC) principles. Thus, the air interface utilized by WTRUs102 a, 102 b, 102 c may be characterized by multiple types of radioaccess technologies and/or transmissions sent to/from multiple types ofbase stations (e.g., a eNB and a gNB).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.11 (i.e.,Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperabilityfor Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×, CDMA2000 EV-DO,Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), InterimStandard 856 (IS-856), Global System for Mobile communications (GSM),Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and thelike.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, an industrialfacility, an air corridor (e.g., for use by drones), a roadway, and thelike. In one embodiment, the base station 114 b and the WTRUs 102 c, 102d may implement a radio technology such as IEEE 802.11 to establish awireless local area network (WLAN). In an embodiment, the base station114 b and the WTRUs 102 c, 102 d may implement a radio technology suchas IEEE 802.15 to establish a wireless personal area network (WPAN). Inyet another embodiment, the base station 114 b and the WTRUs 102 c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. Asshown in FIG. 1A, the base station 114 b may have a direct connection tothe Internet 110. Thus, the base station 114 b may not be required toaccess the Internet 110 via the CN 106/115.

The RAN 104/113 may be in communication with the CN 106/115, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. The data may have varying qualityof service (QoS) requirements, such as differing throughputrequirements, latency requirements, error tolerance requirements,reliability requirements, data throughput requirements, mobilityrequirements, and the like. The CN 106/115 may provide call control,billing services, mobile location-based services, pre-paid calling,Internet connectivity, video distribution, etc., and/or performhigh-level security functions, such as user authentication. Although notshown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or theCN 106/115 may be in direct or indirect communication with other RANsthat employ the same RAT as the RAN 104/113 or a different RAT. Forexample, in addition to being connected to the RAN 104/113, which may beutilizing a NR radio technology, the CN 106/115 may also be incommunication with another RAN (not shown) employing a GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

The CN 106/115 may also serve as a gateway for the WTRUs 102 a, 102 b,102 c, 102 d to access the PSTN 108, the Internet 110, and/or the othernetworks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) and/orthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired and/or wireless communications networksowned and/or operated by other service providers. For example, thenetworks 112 may include another CN connected to one or more RANs, whichmay employ the same RAT as the RAN 104/113 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities (e.g., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks). For example, the WTRU 102 c shown in FIG. 1A may be configuredto communicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram illustrating an example WTRU 102. As shownin FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120,a transmit/receive element 122, a speaker/microphone 124, a keypad 126,a display/touchpad 128, non-removable memory 130, removable memory 132,a power source 134, a global positioning system (GPS) chipset 136,and/or other peripherals 138, among others. It will be appreciated thatthe WTRU 102 may include any sub-combination of the foregoing elementswhile remaining consistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In an embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and/or receive both RF and light signals. It will beappreciated that the transmit/receive element 122 may be configured totransmit and/or receive any combination of wireless signals.

Although the transmit/receive element 122 is depicted in FIG. 1B as asingle element, the WTRU 102 may include any number of transmit/receiveelements 122. More specifically, the WTRU 102 may employ MIMOtechnology. Thus, in one embodiment, the WTRU 102 may include two ormore transmit/receive elements 122 (e.g., multiple antennas) fortransmitting and receiving wireless signals over the air interface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as NR and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs and/or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, a Virtual Reality and/or Augmented Reality (VR/AR) device, anactivity tracker, and the like. The peripherals 138 may include one ormore sensors, the sensors may be one or more of a gyroscope, anaccelerometer, a hall effect sensor, a magnetometer, an orientationsensor, a proximity sensor, a temperature sensor, a time sensor; ageolocation sensor; an altimeter, a light sensor, a touch sensor, amagnetometer, a barometer, a gesture sensor, a biometric sensor, and/ora humidity sensor.

The WTRU 102 may include a full duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for both the UL (e.g., for transmission) anddownlink (e.g., for reception) may be concurrent and/or simultaneous.The full duplex radio may include an interference management unit 139 toreduce and or substantially eliminate self-interference via eitherhardware (e.g., a choke) or signal processing via a processor (e.g., aseparate processor (not shown) or via processor 118). In an embodiment,the WRTU 102 may include a half-duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for either the UL (e.g., for transmission) or thedownlink (e.g., for reception)).

FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the CN 106.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode-B 160 a, for example, may use multiple antennas to transmitwireless signals to, and/or receive wireless signals from, the WTRU 102a.

Each of the eNode-Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the UL and/or DL, and the like. As shown in FIG. 1C, the eNode-Bs 160a, 160 b, 160 c may communicate with one another over an X2 interface.

The CN 106 shown in FIG. 1C may include a mobility management entity(MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN)gateway (or PGW) 166. While each of the foregoing elements are depictedas part of the CN 106, it will be appreciated that any of these elementsmay be owned and/or operated by an entity other than the CN operator.

The MME 162 may be connected to each of the eNode-Bs 162 a, 162 b, 162 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 162 may provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM and/or WCDMA.

The SGW 164 may be connected to each of the eNode Bs 160 a, 160 b, 160 cin the RAN 104 via the S1 interface. The SGW 164 may generally route andforward user data packets to/from the WTRUs 102 a, 102 b, 102 c. The SGW164 may perform other functions, such as anchoring user planes duringinter-eNode B handovers, triggering paging when DL data is available forthe WTRUs 102 a, 102 b, 102 c, managing and storing contexts of theWTRUs 102 a, 102 b, 102 c, and the like.

The SGW 164 may be connected to the PGW 166, which may provide the WTRUs102 a, 102 b, 102 c with access to packet-switched networks, such as theInternet 110, to facilitate communications between the WTRUs 102 a, 102b, 102 c and IP-enabled devices.

The CN 106 may facilitate communications with other networks. Forexample, the CN 106 may provide the WTRUs 102 a, 102 b, 102 c withaccess to circuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. For example, the CN 106 may include,or may communicate with, an IP gateway (e.g., an IP multimedia subsystem(IMS) server) that serves as an interface between the CN 106 and thePSTN 108. In addition, the CN 106 may provide the WTRUs 102 a, 102 b,102 c with access to the other networks 112, which may include otherwired and/or wireless networks that are owned and/or operated by otherservice providers.

Although the WTRU is described in FIGS. 1A-1D as a wireless terminal, itis contemplated that in certain representative embodiments that such aterminal may use (e.g., temporarily or permanently) wired communicationinterfaces with the communication network.

In representative embodiments, the other network 112 may be a WLAN.

A WLAN in Infrastructure Basic Service Set (BSS) mode may have an AccessPoint (AP) for the BSS and one or more stations (STAs) associated withthe AP. The AP may have an access or an interface to a DistributionSystem (DS) or another type of wired/wireless network that carriestraffic in to and/or out of the BSS. Traffic to STAs that originatesfrom outside the BSS may arrive through the AP and may be delivered tothe STAs. Traffic originating from STAs to destinations outside the BSSmay be sent to the AP to be delivered to respective destinations.Traffic between STAs within the BSS may be sent through the AP, forexample, where the source STA may send traffic to the AP and the AP maydeliver the traffic to the destination STA. The traffic between STAswithin a BSS may be considered and/or referred to as peer-to-peertraffic. The peer-to-peer traffic may be sent between (e.g., directlybetween) the source and destination STAs with a direct link setup (DLS).In certain representative embodiments, the DLS may use an 802.11e DLS oran 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS)mode may not have an AP, and the STAs (e.g., all of the STAs) within orusing the IBSS may communicate directly with each other. The IBSS modeof communication may sometimes be referred to herein as an “ad-hoc” modeof communication.

When using the 802.11ac infrastructure mode of operation or a similarmode of operations, the AP may transmit a beacon on a fixed channel,such as a primary channel. The primary channel may be a fixed width(e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling.The primary channel may be the operating channel of the BSS and may beused by the STAs to establish a connection with the AP. In certainrepresentative embodiments, Carrier Sense Multiple Access with CollisionAvoidance (CSMA/CA) may be implemented, for example in in 802.11systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, maysense the primary channel. If the primary channel is sensed/detectedand/or determined to be busy by a particular STA, the particular STA mayback off. One STA (e.g., only one station) may transmit at any giventime in a given BSS.

High Throughput (HT) STAs may use a 40 MHz wide channel forcommunication, for example, via a combination of the primary 20 MHzchannel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHzwide channel.

Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz,and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may beformed by combining contiguous 20 MHz channels. A 160 MHz channel may beformed by combining 8 contiguous 20 MHz channels, or by combining twonon-contiguous 80 MHz channels, which may be referred to as an 80+80configuration. For the 80+80 configuration, the data, after channelencoding, may be passed through a segment parser that may divide thedata into two streams. Inverse Fast Fourier Transform (IFFT) processing,and time domain processing, may be done on each stream separately. Thestreams may be mapped on to the two 80 MHz channels, and the data may betransmitted by a transmitting STA. At the receiver of the receiving STA,the above described operation for the 80+80 configuration may bereversed, and the combined data may be sent to the Medium Access Control(MAC).

Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. Thechannel operating bandwidths, and carriers, are reduced in 802.11af and802.11ah relative to those used in 802.11n, and 802.11ac. 802.11afsupports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space(TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and16 MHz bandwidths using non-TVWS spectrum. According to a representativeembodiment, 802.11ah may support Meter Type Control/Machine-TypeCommunications, such as MTC devices in a macro coverage area. MTCdevices may have certain capabilities, for example, limited capabilitiesincluding support for (e.g., only support for) certain and/or limitedbandwidths. The MTC devices may include a battery with a battery lifeabove a threshold (e.g., to maintain a very long battery life).

WLAN systems, which may support multiple channels, and channelbandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include achannel which may be designated as the primary channel. The primarychannel may have a bandwidth equal to the largest common operatingbandwidth supported by all STAs in the BSS. The bandwidth of the primarychannel may be set and/or limited by a STA, from among all STAs inoperating in a BSS, which supports the smallest bandwidth operatingmode. In the example of 802.11ah, the primary channel may be 1 MHz widefor STAs (e.g., MTC type devices) that support (e.g., only support) a 1MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes.Carrier sensing and/or Network Allocation Vector (NAV) settings maydepend on the status of the primary channel. If the primary channel isbusy, for example, due to a STA (which supports only a 1 MHz operatingmode), transmitting to the AP, the entire available frequency bands maybe considered busy even though a majority of the frequency bands remainsidle and may be available.

In the United States, the available frequency bands, which may be usedby 802.11ah, are from 902 MHz to 928 MHz. In Korea, the availablefrequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the availablefrequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidthavailable for 802.11ah is 6 MHz to 26 MHz depending on the country code.

FIG. 1D is a system diagram illustrating the RAN 113 and the CN 115according to an embodiment. As noted above, the RAN 113 may employ an NRradio technology to communicate with the WTRUs 102 a, 102 b, 102 c overthe air interface 116. The RAN 113 may also be in communication with theCN 115.

The RAN 113 may include gNBs 180 a, 180 b, 180 c, though it will beappreciated that the RAN 113 may include any number of gNBs whileremaining consistent with an embodiment. The gNBs 180 a, 180 b, 180 cmay each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the gNBs 180 a, 180 b, 180 c may implement MIMO technology. For example,gNBs 180 a, 108 b may utilize beamforming to transmit signals to and/orreceive signals from the gNBs 180 a, 180 b, 180 c. Thus, the gNB 180 a,for example, may use multiple antennas to transmit wireless signals to,and/or receive wireless signals from, the WTRU 102 a. In an embodiment,the gNBs 180 a, 180 b, 180 c may implement carrier aggregationtechnology. For example, the gNB 180 a may transmit multiple componentcarriers to the WTRU 102 a (not shown). A subset of these componentcarriers may be on unlicensed spectrum while the remaining componentcarriers may be on licensed spectrum. In an embodiment, the gNBs 180 a,180 b, 180 c may implement Coordinated Multi-Point (CoMP) technology.For example, WTRU 102 a may receive coordinated transmissions from gNB180 a and gNB 180 b (and/or gNB 180 c).

The WTRUs 102 a, 102 b, 102 c may communicate with gNBs 180 a, 180 b,180 c using transmissions associated with a scalable numerology. Forexample, the OFDM symbol spacing and/or OFDM subcarrier spacing may varyfor different transmissions, different cells, and/or different portionsof the wireless transmission spectrum. The WTRUs 102 a, 102 b, 102 c maycommunicate with gNBs 180 a, 180 b, 180 c using subframe or transmissiontime intervals (TTIs) of various or scalable lengths (e.g., containingvarying number of OFDM symbols and/or lasting varying lengths ofabsolute time).

The gNBs 180 a, 180 b, 180 c may be configured to communicate with theWTRUs 102 a, 102 b, 102 c in a standalone configuration and/or anon-standalone configuration. In the standalone configuration, WTRUs 102a, 102 b, 102 c may communicate with gNBs 180 a, 180 b, 180 c withoutalso accessing other RANs (e.g., such as eNode-Bs 160 a, 160 b, 160 c).In the standalone configuration, WTRUs 102 a, 102 b, 102 c may utilizeone or more of gNBs 180 a, 180 b, 180 c as a mobility anchor point. Inthe standalone configuration, WTRUs 102 a, 102 b, 102 c may communicatewith gNBs 180 a, 180 b, 180 c using signals in an unlicensed band. In anon-standalone configuration WTRUs 102 a, 102 b, 102 c may communicatewith/connect to gNBs 180 a, 180 b, 180 c while also communicatingwith/connecting to another RAN such as eNode-Bs 160 a, 160 b, 160 c. Forexample, WTRUs 102 a, 102 b, 102 c may implement DC principles tocommunicate with one or more gNBs 180 a, 180 b, 180 c and one or moreeNode-Bs 160 a, 160 b, 160 c substantially simultaneously. In thenon-standalone configuration, eNode-Bs 160 a, 160 b, 160 c may serve asa mobility anchor for WTRUs 102 a, 102 b, 102 c and gNBs 180 a, 180 b,180 c may provide additional coverage and/or throughput for servicingWTRUs 102 a, 102 b, 102 c.

Each of the gNBs 180 a, 180 b, 180 c may be associated with a particularcell (not shown) and may be configured to handle radio resourcemanagement decisions, handover decisions, scheduling of users in the ULand/or DL, support of network slicing, dual connectivity, interworkingbetween NR and E-UTRA, routing of user plane data towards User PlaneFunction (UPF) 184 a, 184 b, routing of control plane informationtowards Access and Mobility Management Function (AMF) 182 a, 182 b andthe like. As shown in FIG. 1D, the gNBs 180 a, 180 b, 180 c maycommunicate with one another over an Xn interface.

The CN 115 shown in FIG. 1D may include at least one AMF 182 a, 182 b,at least one UPF 184 a, 184 b, at least one Session Management Function(SMF) 183 a, 183 b, and possibly a Data Network (DN) 185 a, 185 b. Whileeach of the foregoing elements are depicted as part of the CN 115, itwill be appreciated that any of these elements may be owned and/oroperated by an entity other than the CN operator.

The AMF 182 a, 182 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N2 interface and may serve as acontrol node. For example, the AMF 182 a, 182 b may be responsible forauthenticating users of the WTRUs 102 a, 102 b, 102 c, support fornetwork slicing (e.g., handling of different PDU sessions with differentrequirements), selecting a particular SMF 183 a, 183 b, management ofthe registration area, termination of NAS signaling, mobilitymanagement, and the like. Network slicing may be used by the AMF 182 a,182 b in order to customize CN support for WTRUs 102 a, 102 b, 102 cbased on the types of services being utilized WTRUs 102 a, 102 b, 102 c.For example, different network slices may be established for differentuse cases such as services relying on ultra-reliable low latencycommunication (URLLC) access, services relying on enhanced massivemobile broadband (eMBB) access, services for machine type communication(MTC) access, and/or the like. The AMF 162 may provide a control planefunction for switching between the RAN 113 and other RANs (not shown)that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro,and/or non-3GPP access technologies such as WiFi.

The SMF 183 a, 183 b may be connected to an AMF 182 a, 182 b in the CN115 via an N11 interface. The SMF 183 a, 183 b may also be connected toa UPF 184 a, 184 b in the CN 115 via an N4 interface. The SMF 183 a, 183b may select and control the UPF 184 a, 184 b and configure the routingof traffic through the UPF 184 a, 184 b. The SMF 183 a, 183 b mayperform other functions, such as managing and allocating UE IP address,managing PDU sessions, controlling policy enforcement and QoS, providingdownlink data notifications, and the like. A PDU session type may beIP-based, non-IP based, Ethernet-based, and the like.

The UPF 184 a, 184 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N3 interface, which may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between the WTRUs 102a, 102 b, 102 c and IP-enabled devices. The UPF 184, 184 b may performother functions, such as routing and forwarding packets, enforcing userplane policies, supporting multi-homed PDU sessions, handling user planeQoS, buffering downlink packets, providing mobility anchoring, and thelike.

The CN 115 may facilitate communications with other networks. Forexample, the CN 115 may include, or may communicate with, an IP gateway(e.g., an IP multimedia subsystem (IMS) server) that serves as aninterface between the CN 115 and the PSTN 108. In addition, the CN 115may provide the WTRUs 102 a, 102 b, 102 c with access to the othernetworks 112, which may include other wired and/or wireless networksthat are owned and/or operated by other service providers. In oneembodiment, the WTRUs 102 a, 102 b, 102 c may be connected to a localData Network (DN) 185 a, 185 b through the UPF 184 a, 184 b via the N3interface to the UPF 184 a, 184 b and an N6 interface between the UPF184 a, 184 b and the DN 185 a, 185 b.

In view of FIGS. 1A-1D, and the corresponding description of FIGS.1A-1D, one or more, or all, of the functions described herein withregard to one or more of: WTRU 102 a-d, Base Station 114 a-b, eNode-B160 a-c, MME 162, SGW 164, PGW 166, gNB 180 a-c, AMF 182 a-ab, UPF 184a-b, SMF 183 a-b, DN 185 a-b, and/or any other device(s) describedherein, may be performed by one or more emulation devices (not shown).The emulation devices may be one or more devices configured to emulateone or more, or all, of the functions described herein. For example, theemulation devices may be used to test other devices and/or to simulatenetwork and/or WTRU functions.

The emulation devices may be designed to implement one or more tests ofother devices in a lab environment and/or in an operator networkenvironment. For example, the one or more emulation devices may performthe one or more, or all, functions while being fully or partiallyimplemented and/or deployed as part of a wired and/or wirelesscommunication network in order to test other devices within thecommunication network. The one or more emulation devices may perform theone or more, or all, functions while being temporarilyimplemented/deployed as part of a wired and/or wireless communicationnetwork. The emulation device may be directly coupled to another devicefor purposes of testing and/or may performing testing using over-the-airwireless communications.

The one or more emulation devices may perform the one or more, includingall, functions while not being implemented/deployed as part of a wiredand/or wireless communication network. For example, the emulationdevices may be utilized in a testing scenario in a testing laboratoryand/or a non-deployed (e.g., testing) wired and/or wirelesscommunication network in order to implement testing of one or morecomponents. The one or more emulation devices may be test equipment.Direct RF coupling and/or wireless communications via RF circuitry(e.g., which may include one or more antennas) may be used by theemulation devices to transmit and/or receive data.

WTRU, UE, and user may be used interchangeably herein.

In NR for 5G wireless systems, ultra-reliable low latency communication(URLLC) systems have a need for mechanisms that increase the reliabilityof the control channel (e.g., the PDCCH), for example by lowering theblock error rate (BER) and lowering the probability of blocking.

As used herein, a reference symbol may include a symbol (e.g., which maybe expressed as a complex number) that is fixed and known and used as apilot symbol. A reference signal may include the time domain signal thatis generated by processing reference symbols. For example, in OFDM,reference symbols may be complex numbers fed into n Inverse DiscreteFourier Transform (IDFT) block and the reference signal may be theoutput of the IDFT block. The downlink control information (DCI) mayinclude a set of bits that are transmitted over a PDCCH carrying controlinformation for a WTRU (user) or a group of WTRUs (users).

A resource element (RE) may include one OFDM symbol on one subcarrier. Aresource element group (REG) may include a group of REs used as buildingblocks of a control channel element (CCE) that assigns resource elementsto a WTRU. REG Bundles are REGs that are adjacent in time or frequencyand that are grouped together with the same associated precoders.NR-REG, NR-CCE and NR-PDCCH may be used to refer to a REG, a CCE, and aPDCCH for NR in 5G wireless systems.

In 5G NR, a REG may be the smallest building block for the PDCCH. Forexample, each REG may consist of 12 REs on one OFDM symbol in time andone resource block (RB) in frequency. In each REG, 9 REs may be used forcontrol information and 3 REs may be used for demodulation referencesignals (DMRSs). Multiple REGs (e.g., 2, 3, or 6), adjacent in time orfrequency, may form a REG bundle used with the same precoder and havingDMRSs that are used together for channel estimation. 6 REGs (e.g., inthe format of 1, 2, or 3 REG bundles) may form one CCE for PDCCH. EachPDCCH may consist of one or multiple CCEs (e.g., 1, 2, 4, 8, or 16 CCEs)and the number of CCEs for a PDCCH may be referred to as the aggregationlevel (AL) of the PDCCH.

Mapping of REG bundles may include the following modes: interleavingmode and non-interleaving mode. In the non-interleaving mapping,consecutive REG bundles (i.e., adjacent in frequency) form a CCE andCCEs adjacent in frequency form a PDCCH. In the interleaving mapping,REGs are interleaved (or permuted) before being mapped to CCEs, whichmay result in some (or all) non-adjacent REG bundles in one CCE and some(or all) non-adjacent CCEs in one PDCCH.

A Control Resource Set (CORESET) may be configured by its frequencyassignment (e.g., in chunks of 6 RBs), the length in time (1-3 OFDMsymbols), the type of REG bundle, and the type of mapping from REGbundles to CCEs (i.e., interleaving or non-interleaving). In an example,in each bandwidth part (BWP), there may be up to 3 CORESETs (12 CORESETsin all 4 possible bandwidth parts).

A WTRU may be assigned with a set of PDCCH candidates to monitor duringthe blind detection of PDCCH, which is referred to as the search spaceor the set of search spaces (e.g., for multiple ALs). Each set of searchspaces may be configured by its associated CORESET, the number ofcandidates with each AL, and the monitoring occasions. The monitoringoccasions may be determined by the monitoring periodicity (e.g., interms of slots), monitoring offset, and monitoring pattern (14 bitscorresponding to all possible patterns of symbols inside a slot).

Example methods for providing sufficient resources for transmission ofthe downlink control channel for URLLC WTRUs may include the preemptionof an eMBB control channel(s) in the presence of a URLLC channel(s). Inan example, resources may be assigned for downlink control channeltransmission may be used for eMBB WTRUs. The downlink control channelfor URLLC WTRUs may receive higher priority than the downlink controlchannel for eMBB WTRUs. For example, the presence of the PDCCH for URLLCWTRUs may preempt or partially preempt the transmission of the scheduledPDCCH for eMBB WTRUs.

To lower the probability of locking the PDCCH of URLLC WTRUs, URLLCWTRUs may be given higher priority over the PDCCH of eMBB WTRUs. In anexample, in scheduling of PDCCH of different WTRUs based on their searchspaces, a gNB may first schedule the PDCCH for URLLC WTRUs. The gNB maythen schedule the PDCCH for eMBB WTRUs by removing the PDCCH candidatesthat are already fully or partially used for URLLC WTRUs from the searchspaces corresponding to the active eMBB WTRUs. Enabling eMBB PDCCHpreemption may reduce or eliminate blocking and increase reliability ofPDCCH for URLLC WTRUs by allowing usage of more resources.

Example methods may be used for partially preempting the PDCCH for eMBBWTRUs in the presence of PDCCH for URLLC WTRUs. Two differentoverlapping CORESETs may be assigned for the PDCCH of eMBB WTRUs and thePDCCH of URLLC WTRUs, respectively. The different overlapping CORESETsmay have different REG bundling types and/or transmission modes (i.e.interleaving vs. non-interleaving). To reduce delay for URLLC WTRUs, theCORESET assigned for the PDCCH of the URLLC WTRUs may be allocated onthe first OFDM symbol of the slot and the CORESET assigned for the PDCCHof the eMBB WTRUs may be multi-symbol. When a PDCCH candidate in theURLLC CORESET is scheduled, transmission of eMBB PDCCH may be preemptedon the REGs that are shared with the transmitted URLLC PDCCH. Whenpreemption takes place on the shared REGs, rate matching may be employedto match the code rate of the eMBB PDCCH based on the remainingavailable REGs of the PDCCH. FIG. 2 is a scheduling diagram of anexample scheduling method 200 for partially preempting the PDCCH foreMBB WTRUs in the presence of PDCCH for URLLC WTRUs. A PDCCH 204 isscheduled for the URLLC WTRUs on the first OFDM symbol 201 and partiallypreempts transmission of the PDCCH 210 on the two-symbol CORESET 206(across symbols 201 and 202) for the eMBB WTRUs. Data 208 may betransmitted following the transmission of the PDCCHs 204 and 210.

At the receiver, an eMBB WTRU may detect the preempted REGs of a PDCCHcandidate by comparing the channel estimates from the DMRS of one REGbundle. For example, in the case that REG bundling is done in time forthe eMBB CORESET and the URLLC CORESET covers only the first symbol ofthe slot, if the eMBB WTRU observes a large discrepancy between thechannel estimate for the REG on the first symbol and the channelestimate for other REGs of that REG bundle, the eMBB WTRU may assumethat the REG on the first symbol is used by a URLLC WTRU and mayidentify it as a preempted REG. The eMBB WTRU may remove the preemptedREGs from the set of REGs that are used for channel estimation (andPDCCH detection) and may complete the channel estimation procedure byjoint channel estimation of the remaining REGs for each REG bundle. TheeMBB WTRU may perform blind decoding on the remaining REGs based on thechannel estimation and the received signal and apply the rate matchingassociated with the number of remaining REGs.

Based on the number of remaining REGs in each REG bundle, the quality ofthe channel estimation and, therefore, the quality of soft decisions forthe received coded bits based on those REGs, may be different.Therefore, the eMBB WTRU may use the information about the removed REGsfrom each bundle (and related information such as the number of DMRSused for channel estimation for an REG bundle) for the decoding process.For example, the number of DMRS used for channel estimation may affectthe quality of channel estimation and this may be taken to account whencalculating log-likelihood ratio (LLR) of the received coded bits in thedecoding process (i.e. the quality of soft decisions in the decodingprocess).

After decoding, similar to the regular blind detection of the PDCCH, theeMBB WTRU may check a cyclic redundancy code (CRC) to determine if thedecoded data is correct and whether it is associated with the eMBB'sradio network temporary identifier (RNTI). An indication of a need forthe blind detection procedure (i.e., the existence of possibleoverlapping URLLC PDCCH on a part of the eMBB CORESET) and/or extraparameters that may be useful in the blind detection procedure may ormay not be included in the eMBB CORESET configuration provided by thegNB radio resource control (RRC) layer. The extra parameters may includeinformation such as the overlapped resource region (e.g., expressed interms of the OFDM symbol index and the RBs, for example with granularityof 6 RBs, which is used for frequency configuration of CORESETs in 5GNR) and/or the transmission mode of the overlapping URLLC CORESET. Ifthe indication of a need for the blind detection procedure is notincluded in the CORESET configuration received from the gNB, the WTRUmay implicitly derive the overlapping parts of the CORESETs based onsome predefined patterns. For example, assuming the eMBB WTRU isconfigured with a relatively wideband CORESET on the first OFDM symbol(e.g., a single-symbol CORESET as wide as the bandwidth part), and anarrow-band multi-symbol CORESET (e.g., a multi-symbol CORESET muchsmaller than the bandwidth part) which overlaps with the single-symbolCORESET, the eMBB WTRU may assume that the REGs on the first OFDM symbolare preempted according to an a priori known pattern. This method may beuseful when the URLLC CORESET is single-symbol and the eMBB CORESET ismulti-symbol, and may be applied when both CORESETs cover the samesymbol(s), but with different modes of transmission (e.g., oneinterleaved and one non-interleaved).

FIG. 3 is a flow diagram of an example method 300 for partial preemptionof PDCCH for eMBB in the presence of PDCCH for URLLC. The example method300 may be performed by the WTRU of the eMBB user. For example, theexample method 300 may be performed when the URLLC CORESET issingle-symbol and the eMBB CORESET is multi-symbol. At 302, the eMBBWTRU may obtain a CORESET configuration for the eMBB CORESET and searchspace parameters (e.g., through RRC signaling). The CORESETconfiguration may include a preemption indication parameter (a PDCCHpreemption indicator). At 304, the eMBB WTRU may determine if the eMBBCORESET configuration includes an indication of possible (partial)preemption (i.e., an indication that PDCCH preemption is enabled). If apreemption indicator is not used, the eMBB WTRU may implicitly derivethe overlapping parts of the CORESETs to determine the possibility ofpreemption as described above. If the indication of possible preemptionis detected, then at 306, the eMBB WTRU may examine each REG bundle andcheck the consistency of channel estimation to identify preempted REGs.At 308, the eMBB WTRU may remove the preempted REGs from the set of REGsthat are used for channel estimation of the REG bundle (and PDCCHdetection) and perform channel estimation based on (e.g., the DMRS of)the remaining REGs of each REG bundle. At 310, the eMBB WTRU may detectthe PDCCH by perform blind decoding, based on the received signal, onthe remaining REGs of each REG bundle (and avoiding the preempted REGs)and perform rate matching associated to the number of remaining REGs ineach REG bundle. At 312, the eMBB WTRU may check CRC of the data decodedfrom the remaining REGs to detect errors and may receive the PDCCH(e.g., determine if the PDCCH is for the eMBB WTRU by checking the RNTI,etc.). If an indication of possible partial preemption is not detected,then at 314, the eMBB WTRU may perform joint channel estimation for eachREG bundle. At 316, the eMBB may perform blind decoding of the PDCCHcandidates using all REGs of each PDCCH candidate. At 318, the eMBB WTRUmay check CRC of the data decoded from all REGs to detect errors and mayreceive the PDCCH (e.g., determine if the PDCCH is for the eMBB WTRU bychecking the RNTI, etc.)

Example methods may be used for full preemption of the PDCCH for eMBBWTRUs when overlapped with the PDCCH for URLLC WTRUs. In an example, thedraft scheduling of PDCCH for eMBB WTRUs may be done independently ofthe scheduling of PDCCH for URLLC WTRUs. The transmission of a scheduledPDCCH for an eMBB WTRU may be preempted when the eMBB PDCCH candidate isneeded for the PDCCH of a URLLC WTRU or when the eMBB PDCCH candidateoverlaps with the PDCCH scheduled for URLLC. This method of fullypreempting the PDCCH of eMBB users may result in a large probability ofblocking for eMBB WTRUs. In order to avoid large probabilities ofblocking, a small number of additional spare PDCCH candidates on thesame CORESET or on another CORESET may be assigned to be monitored byeMBB WTRUs when an eMBB WTRU cannot find and decode its intended PDCCHin its default search space.

FIG. 4 is another scheduling diagram of an example scheduling method 400for partially preempting the PDCCH for eMBB WTRUs in the presence ofPDCCH for URLLC WTRUs. The URLLC CORESET 404 (for URLLC WTRUs to searchfor PDCCH) occupies OFDM symbol 401 (spanning all frequencies) and theeMBB CORESET 406 (for eMBB WTRUs to search for PDCCH) occupies a subsetof frequencies across OFDM symbols 401 and 402, thereby partiallyoverlapping with the URLLC CORESET 504 on certain carrier frequencies ofOFDM symbol 401. According to the example of FIG. 4 , multiple REGbundles 408 for URLLC PDCCH are scheduled in OFDM symbol 401, andmultiple REG bundles 410 are scheduled in OFDM symbols 401 and 402, suchthat eMBB PDCCH is preempted on REG 412 by the URLLC PDCCH because ofthe CORESET overlap. Data may be transmitted (e.g., physical downlinkshared channel (PDSCH) 414) following the transmission of the PDCCHs onOFDM symbols 401 and 402.

FIG. 5 is a scheduling diagram of an example scheduling method 500 forfully preempting the PDCCH for eMBB WTRUs when overlapped with the PDCCHfor URLLC WTRUs. As shown in FIG. 5 , a large or main CORESET 504 forboth eMBB and URLLC WTRUs may be configured on the first OFDM symbol 501of the slot (e.g., symbol 0, if they are numbered from zero), and asmaller (spare) CORESET 506 may be configured on the second (and/orthird) OFDM symbol 502 of the slot containing a small number of PDCCHcandidates for the eMBB WTRUs in the case that their intended PDCCH ispreempted on the main CORESET 504. The structure of the smaller CORESET506, which contains the spare PDCCH candidates and the number and thesize (aggregation level) of those spare PDCCH candidates, may beconfigured by the RRC for example. The location of the spare PDCCHcandidates with different aggregation levels inside the spare CORESET506 may be fixed or obtained through the hashing function that isdefined for search spaces. All active eMBB WTRUs may have the samesearch space inside the spare CORESET 506, or their corresponding searchspaces may be different. Data 508 may be transmitted following thetransmission of the PDCCHs in CORESETs 504 and/or 506.

The methods for preempting the PDCCH of eMBB WTRUs described herein maynot affect the behavior of URLLC WTRUs, and may affect the behavior foreMBB WTRUs. For example, an eMBB WTRU may be explicitly or implicitlyconfigured by a gNB (e.g., using RRC signaling) to only blind decode itsPDCCH candidates in the spare CORESET or in the spare search space ifthe blind decoding of its PDCCH candidates in the main CORESET or in itsmain set of search spaces is unsuccessful. The implicit configurationfor the eMBB WTRU behavior for the spare CORESET may be done duringCORESET configuration by including an indication of the spare status ofthe spare CORESET and/or the index of the main CORESET associated withthe spare CORESET.

Methods may be used for transmission of URLLC DCI on multiple PDCCHs bythe gNB, and corresponding methods for a receiving URLLC WTRU, toincrease the reliability of DCI transmission for URLLC WTRUs. In anexample, the reliability of DCI transmission for URLLC may be increasedby adding redundancy in PDCCH for a URLLC user. For example, the sameDCI may be transmitted over two or more PDCCHs for a URLLC WTRU, orjoint redundancy for multiple DCIs intended for a URLLC WTRU may betransmitted by the gNB.

In an example for enhancing the reliability of an URLLC control channel,the transmission of the same DCI content may be repeated on multiplePDCCHs. The PDCCH transmission may be repeated with the same rate and/orthe same transmission mode (e.g., by repeating the same PDCCH on twodifferent locations) or may be repeated using different rates (e.g.,using PDCCHs with different aggregation levels) and/or differenttransmission modes (e.g., using interleaved versus non-interleavedmode).

In an example, the same DCI may be transmitted over two or more PDCCHcandidates of a same search space. In this example, two or more PDCCHcandidates (with the same or different aggregation levels) may be usedat the same time by the gNB to transmit one DCI to a WTRU (e.g., a URLLCWTRU). The number of or the maximum number of simultaneous PDCCHsscheduled for the WTRU may be indicated in the configuration of thesearch space of the WTRU (e.g., using RRC signaling), and/or may beindicated in the CORESET configuration for all associated WTRUs.

In another example, the same DCI may be transmitted over two or morePDCCH candidates of different search spaces on a same CORESET. In thisexample, two or more sets of search spaces (e.g., each set of searchspaces may contain several candidates with different aggregation levels)may be assigned to a WTRU. The WTRU may expect and monitor for ascheduled PDCCH on each of assigned sets of search spaces. The RRCconfiguration may indicate whether the aggregation levels of themultiple PDCCHs, that are carrying the same DCI, are the same ordifferent.

In the case that the aggregation levels of the multiple PDCCHs are thesame, there may be a one-to-one correspondence between the candidates ofthe sets of search spaces, as shown in FIG. 6 . FIG. 6 is a schedulingdiagram of an example method 600 for transmission of the same DCI overtwo PDCCH candidates, REG bundles 606 and REG bundles 608, of twodifferent sets of search spaces 601 and 602, respectively on a sameCORESET 604. In this case, the scheduling of the correspondingcandidates, REG bundles 606 and REG bundles 608, in the different setsof search spaces 601 and 602, respectively, may be linked to each other(i.e. corresponding candidates may be scheduled simultaneously) and thiscorrespondence may be explicitly or implicitly indicated in the RRCconfiguration of the CORESET 604 and/or the sets of search spaces 601and 602. This correspondence may help the WTRU simplify the blinddetection of the PDCCH received on the REG bundles 606 and 608. In theexample of FIG. 6 , each of the two or more sets of search spaces 601and 602 are on a single OFDM symbol respectively inside a multi-symbolCORESET 604, and may be associated with different beams.

In the example above, the one-to-one correspondence between the PDCCHcandidates of two or more different sets of search spaces may beimplemented using the same RNTI and the same set of aggregation levelsand numbers of candidates for each aggregation level as the parametersfor the hashing functions of the two or more sets of search spaces. Whenthe sets of aggregation levels and the numbers of candidates of eachaggregation level for the two or more sets of search spaces is the same,the one-to-one correspondence may be based on the index of candidatesfor each aggregation level. In addition, the rule for one-to-onecorrespondence may be pre-specified or configured by the gNB (e.g.,using RRC signaling). This one-to-one correspondence between the PDCCHcandidates of two or more different sets of search spaces may be insideone CORESET or between two or more different sets of search spaces fromdifferent CORESETs and/or different monitoring occasions.

At the receiver, the WTRU may perform a blind search for all the sets ofsearch spaces intended for the DCI independently by checking the RNTIthrough CRC checking for each PDCCH candidate separately. In an example,if there is one-to-one correspondence between the PDCCH candidates oftwo or more different sets of search spaces, the WTRU may first performthe channel estimation separately for each of the PDCCH candidates andthen may add the received symbols of the corresponding PDCCH candidatestogether, or combine the soft decoding information of the correspondingPDCCH candidates, and then do the decoding and CRC check for thecorresponding PDCCH candidates together. This method of combining thesoft decoding information may be used if the set of bits that are sentover the corresponding PDCCHs are the same, which is the case if the DCIis the same for the corresponding PDCCH and the channel coding and CRCis the same for the corresponding PDCCH.

In another example, the same DCI may be transmitted over two or morePDCCHs on different CORESETs. In this case, the same DCI may betransmitted by two or more PDCCHs on different CORESETs for a WTRU. Anindication of possible redundant transmissions may be included in theCORESET configuration or the configuration of the search spaces (e.g.,via RRC signaling) or the physical broadcast channel (PBCH). Themultiple CORESETs containing the multiple PDCCHs transmitting the sameDCI may be on the same or different BWPs.

In another example, the multiple CORESETs containing the multiple PDCCHstransmitting the same DCI may be on different OFDM symbols. In thiscase, the CORESETs and the PDCCH candidates carrying that DCI may beassociated with different beams. In addition, the CORESETs containingthe PDCCHs may have different or the same mode of transmission (e.g.,interleaved vs non-interleaved).

In the case of the same DCI being transmitted over multiple PDCCHs onthe same CORESET, the WTRU may assume that the DMRS antenna portassociated with multiple PDCCHs are quasi co-located with respect todelay spread, Doppler spread, Doppler shift, average delay, and/orspatial reception (Rx) parameters. In the case of multiple PDCCHstransmitted on different CORESETs, the WTRU may not assume that the DMRSantenna port associated with multiple PDCCHs are quasi co-located withrespect to delay spread, Doppler spread, Doppler shift, average delay,and/or spatial Rx parameters. In the latter case, the WTRU may performchannel estimation individually on each PDCCH.

In the case of the WTRU receiving the same DCI over multiple PDCCHs(e.g., the same downlink allocation or uplink grant), the WTRU maymonitor a set of PDCCH candidates within the same or multiple searchspaces. If the CRC scrambled by cell RNTI (C-RNTI) was checked for oneof the PDCCH candidates, the WTRU may continue monitoring for otherPDCCH candidates with CRC scrambled by an identical WTRU-specificC-RNTI. In this scenario, the WTRU may use detected DCIs over multiplePDCCHs with the identical C-RNTI to improve the control channeldetection reliability. In the case of the same DCI being transmitted onmultiple PDCCHs, the WTRU may receive one PDCCH on the common searchspace and another PDCCH on a WTRU-specific search space, even in thecase that the CRC for multiple PDCCHs is scrambled by an identicalWTRU-specific C-RNTI.

In another example, PDCCH repetition may be implemented throughmulti-CORESET search spaces. For example, in order to facilitatescheduling and blind detection of repeated DCI, the WTRU may beconfigured with a search space that is associated with multipleCORESETs. A search space may be configured semi-statically throughhigher layer signaling (e.g. RRC) by a set of parameters, such as theassociated CORESET. In an example method, multiple CORESETs may beassociated with one search space (or one set of search spaces), and eachindex of the corresponding hashing function may be associated withmultiple PDCCH candidates (e.g., one from each CORESET). The linkedPDCCH candidates (on different CORESETs) may be used to repeat the samecontrol information (DCI). At the receiver, the WTRU may blindly detectits PDCCH by first combining the linked PDCCH candidates from differentCORESETs (based on its search space or set of search spaces) and thendecode the linked PDCCH candidates and check CRC. In an example, theWTRU may decode each PDCCH candidate separately (and check CRC of eachcandidate separately). Separate decoding of the corresponding PDCCHcandidates may provide enhanced reliability through multiple trials.

In PDCCH repetition through multi-CORESET search spaces, theCORESET-related bit field of the search space configuration may indicatea combination of CORESETs (e.g., instead of one CORESET). An example ofan indication of a combination of CORESETs is to use 12 bits to indicatethe association of a subset of the configured CORESETs to a search space(or a set of search spaces), for example in place of the currentparameter ControlResourceSetId (or “CORESET-ID”) in 5G NR. The mappingof the CORESET-related bits in the search space configuration to thesubset of CORESETs may be pre-specified in the standard specificationsas a table or may be indicated as the inclusion/exclusion of the ithCORESET using 0 or 1 as the ith bit index (i from 0 to 11) in theCORESET-related bit field of the search space configuration.

In another example, undefined cases of CORESET ID may be used to definecombinations of multiple CORESETs. For example, when at most 12 CORESETs(0-11) are defined and 4 bits are used for indicatingControlResourceSetId (or “CORESET-ID”) in the configuration of searchspace, the last four values (12-15) may be used to indicate a pair ofCORESETs, as shown in Table 1.

TABLE 1 An example of a ControlResourceSetID parameter includingmulti-CORESET options for search space configuration Associated CORESETControlResourceSetID or pairs of CORESETs 0 0 1 1 2 2 3 3 4 4 5 5 6 6 77 8 8 9 9 10 10 11 11 12 1.2 13 1.4 14 1.7 15 1.10

FIG. 7 shows a flow diagram of an example WTRU procedure 700 for PDCCHrepetition through multi-CORESET search spaces together with softcombination for blind detection. After receiving search space (SS)configuration 702 (e.g., through RRC or other higher layer signaling), aWTRU may determine, at 704, if the configured search space issingle-CORESET or multi-CORESET. For example, the WTRU may make thedetermination based on a received flag (indicator) bit (e.g., receivedin the search space configuration) or implicitly based on the number ofCORESET-related bits in the search space configuration (e.g., defaultmay be a single-CORESET search space).

If the WTRU identifies a multi-CORESET search space, then at 706 theWTRU may determine the associated CORESETs based on the CORESET-relatedbits of the search space configuration and a pre-specified mapping(e.g., based on the standard specifications). At 708, the WTRU maydetermine the corresponding pairs (or tuples) of PDCCH candidates thatare supposed to carry the same DCI (one on each CORESET) by determiningthe sets of PDCCH candidates associated with each CORESET and theone-to-one correspondence among the PDCCH candidates in those sets. Forblind detection, at 710, the WTRU may perform channel estimation foreach REG bundle of PDCCH candidates separately. At 712, the WTRU mayperform blind detection for each corresponding pair (or tuple) of PDCCHcandidates by combining symbols (or soft decoding information from thesymbols) of the PDCCH candidates belonging to the pair (or tuple) anddecoding each pair (or tuple) and checking the CRC.

If the WTRU identifies a single-CORESET search space, then at 714 theWTRU may determine the associated CORESET through the CORESET-relatedbit filed in the SS configuration. At 716, the WTRU may determine theset of PDCCH candidates on each monitoring occasion based on the SSconfiguration parameters. At 718, the WTRU may perform blind detectionby performing channel estimation and decode each PDCCH candidate andchecking CRC.

Joint redundancy may be used for multiple DCIs intended for a URLLCWTRU. As discussed in examples above, multiple DCIs may be intended forthe same WTRU, corresponding to multiple streams or layers of data. Inthis case, in addition or alternatively to repeating each DCI onmultiple PDCCHs, enhanced reliability through redundancy may be achievedusing joint redundancy for the multiple DCIs. To achieve jointredundancy, network coding schemes may be used to enhance reliability.For example, if two DCIs A and B have the same size and DCI A is sent bya first PDCCH to the WTRU and DCI B is sent by a second PDCCH to theWTRU, then DCI+DCI B (e.g., added as an XOR operation) may betransmitted by a third PDCCH to the same WTRU to increase reliability.

Dropping rules may be designed to satisfy the limits on blind decodingby WTRU. In 5G NR, as well as LTE, limits on the maximum number of blinddecodes in a time slot may be assumed for a WTRU. To limit thecomplexity of channel estimation by the WTRUs, the number of CCEs thatare covered by the PDCCH candidates that a WTRU may blindly decode in aslot may be limited. The inherent randomness of hashing functions thatspecify the sets of search spaces for a WTRU may make the number ofcovered CCEs (or the number of CCEs in the footprint of the sets ofsearch spaces for that WTRU) variable. Having different types of PDCCHswith different possible monitoring rates may result in a fluctuation ofthe number of PDCCH candidates to be blindly decoded. Therefore,limiting the parameters for the sets of search spaces such that thenumber of blind decodes and the number of covered CCEs remain in anappropriate range for all conditions may be prohibitive.

In an example, the search space parameters may be designed such that thelimits on the number of candidates and the number of covered CCEs aresatisfied with a high probability. For the low-probability cases thatexceed the limits, rules may be set to drop some of the PDCCH candidatesfrom the blind decoding process to satisfy the hard limits. Droppingrules may be based on a number of factors and variables. For example,dropping rules may be fixed rules that are specified by the technicalspecification and/or semi-static rules that are configured by higherlayer signaling (e.g. RRC). The dropping rules may be based on ahierarchy of priorities for different types of PDCCHs, monitoringoccasions and/or other parameters. The rules for dropping a PDCCHcandidate from the blind decoding may be based on the PDCCH candidate'saggregation level (e.g., having lowest priority compared to other PDCCHcandidates). The dropping rules and the associated order of prioritiesmay be based on a combination of different properties, such as thoseproperties discussed above. The WTRU and/or the gNB may have knowledgeof the dropping rules, to prevent the WTRU from performing a blindsearch on the dropped PDCCH candidate and/or the gNB scheduling adropped PDCCH candidate. In an example, a fixed set of dropping rulesmay be used, and/or multiple sets of dropping rules may be used, suchthat one dropping rules set may be semi-statically chosen or configuredby the gNB, and the WTRU is informed of the chosen dropping rules setthrough mechanisms such as RRC configuration of CORESETs or searchspaces.

An example hierarchy of priorities for different CORESETs and PDCCHcandidates with different aggregation levels inside each CORESET may beas follows: (1) All PDCCH candidates on single-symbol CORESETs on thefirst OFDM symbol of the slot; (2) All PDCCH candidates on single-symbolCORESETs on the other OFDM symbols of the slot; and (3) PDCCH candidateson multi-symbol CORESETs with smaller candidates (with smalleraggregation levels) having higher priority.

In an example, the rules for dropping a PDCCH candidate from the blindsearch may be based on the number of CCEs that are not non-overlappingwith CCEs of the other PDCCH candidates of the set of search spaces. Inother words, the PDCCH candidate(s) for which removal will result in themost number of CCEs being removed from the pool for channel estimationmay be chosen to be dropped from the blind search. In the case thatmultiple PDCCH candidates with same metric are identified, their indexin the search space may dictate their precedence.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

What is claimed is:
 1. A wireless transmit/receive unit (WTRU)configured to detect a physical downlink control channel (PDCCH)transmission, the WTRU comprising: a receiver configured to receiveconfiguration information for a control resource set (CORESET), theCORESET comprising a plurality of resource element groups (REGs) and theconfiguration information including a PDCCH preemption indicator thatindicates that PDCCH preemption is enabled; and a processor and thereceiver configured to, based on the PDCCH preemption indicatorindicating that PDCCH preemption is enabled, detect the PDCCHtransmission by performing blind decoding, based on a received signal,on REGs in the CORESET that are not preempted.
 2. The WTRU of claim 1further configured to identify preempted REGs from the CORESET andperform channel estimation on the REGs in the CORESET that are notpreempted.
 3. The WTRU of claim 1 further configured to identifypreempted REGs from the CORESET by comparing channel estimates for eachof a plurality of REG bundles in the CORESET.
 4. The WTRU of claim 1,wherein the detected PDCCH transmission is rate matched around thepreempted REGs.
 5. The WTRU of claim 1, wherein the processor is furtherconfigured to check a cyclic redundancy code (CRC) of the receivedsignal to determine if the PDCCH transmission was decoded without error.6. The WTRU of claim 2, wherein the CORESET is an enhanced mobilebroadband (eMBB) CORESET, and the preempted REGs are shared with anultra-reliable low latency communication (URLLC) PDCCH transmission. 7.The WTRU of claim 1, wherein the eMBB CORESET overlaps, at least inpart, with a ultra-reliable low latency communication (URLLC) CORESET.8. The WTRU of claim 1, wherein: the receiver is further configured toreceive second configuration information for a spare CORESET, the spareCORESET occupying at least one orthogonal frequency divisionmultiplexing (OFDM) symbol that is different from the CORESET; and on acondition that the blind decoding in the CORESET is unsuccessful, theprocessor is further configured to blind decode the PDCCH transmissionin the spare CORESET or in a spare search space.
 9. The WTRU of claim 1configured as an eMBB WTRU.
 10. A method for detecting a physicaldownlink control channel (PDCCH) transmission, performed by a wirelesstransmit/receive unit (WTRU), the method comprising: receivingconfiguration information for a control resource set (CORESET), theCORESET comprising a plurality of resource element groups (REGs) and theconfiguration information including a PDCCH preemption indicator thatindicates that PDCCH preemption is enabled; and based on the PDCCHpreemption indicator indicating that PDCCH preemption is enabled,detecting the PDCCH transmission by performing blind decoding, based ona received signal, on REGs in the CORESET that are not preempted. 11.The method of claim 10 further comprising identifying preempted REGsfrom the CORESET and performing channel estimation on the REGs in theCORESET that are not preempted.
 12. The method of claim 10 furthercomprising identifying preempted REGs from the CORESET by comparingchannel estimates for each of a plurality of REG bundles in the CORESET.13. The method of claim 10, wherein the detected PDCCH transmission israte matched around the preempted REGs.
 14. The method of claim 10,further comprising: checking a cyclic redundancy code (CRC) of thereceived signal to determine if the PDCCH transmission was decodedwithout error.
 15. The method of claim 11, wherein the CORESET is anenhanced mobile broadband (eMBB) CORESET, and the preempted REGs areshared with an ultra-reliable low latency communication (URLLC) PDCCHtransmission.
 16. The method of claim 15, wherein the eMBB CORESEToverlaps, at least in part, with a ultra-reliable low latencycommunication (URLLC) CORESET.
 17. The method of claim 10, furthercomprising: receiving second configuration information for a spareCORESET, the spare CORESET occupying at least one orthogonal frequencydivision multiplexing (OFDM) symbol that is different from the CORESET;and on a condition that the blind decoding in the CORESET isunsuccessful, blind decoding the PDCCH transmission in the spare CORESETor in a spare search space.
 18. The method of claim 10, wherein the WTRUis configured as an eMBB WTRU.